Adjustable depth chuck



May 24, 1938. F. R. BROWN ADJUSTABLE DEPTH CHUCK Filed July s, 1936 lllllli llllHl III! INVENTOR W l1 5W".

ATTORNEY H v =FE=====U ll ////////////J////// M/%mq\ 4. 13 y, m fififlz a 5g 5 f Wm M 4 I f E i v 2 m 3 J 5 3 Z Patented May 24, 1938 UNITED STATES PATENT OFFICE ADJUSTABLE DEPTH CHUCK Application July 3, 1936, Serial No. 88,741

1 Claim.

This invention relates to improvements in chucks, more particularly to drill chucks. Heretofore, most drill chucks relied on the pressure of the tool gripping jaws on the sides of the drill to prevent any slippage thereof.

The main object of the invention is to prevent end slippage of the tool in drill chucks. To this end the chuck is provided with a stop which abuts the inner end of the drill to prevent it from slipping endwise when under pressure in the work, thereby eliminating mutilation of drill shanks and strain on the chuck while permitting the drill to run true.

A further object of the invention is to permit manual adjustment of the stop to permit the drill to be set for diflerent depths of holes. With this end in view, there is provided a hollow body within which the stop is mounted to abut the inner end of the drill, the stop being held by a 2 block slidably mounted in a longitudinal slot inthe body and surrounded by a sleeve which has threads engaging threads on the protruding ends of the block. By turning the sleeve the stop may be thus moved axially to set the drill for the desired depth of hole. Furthermore, the stop has a reduced portion which has a diameter small enough to enter between the tool gripping jaws, wherefore exceedingly short drill lengths may be used. With these and other objects not specifically mentioned in view, the invention consists in certain constructions and combinations hereinaiter described and specifically set forth in the claim hereunto appended.

In the accompanying drawing, which forms a p rt of this specification and in which like characters of reference indicate the same or like parts: Fig. 1 is a side elevation, partly shown in section of the adjustable depth chuck; Fig. 2 is a sectional side elevation of the same taken on line 2-2 of Fig. 1; and

Fig. 3 is a sectional plan view of the chuck, taken on line 3-3 of Fig. 1.

Referring to the drawing, wherein a suitable 5 embodiment of the invention is illustrated, the adjustable depth chuck consists of a body In which is provided with an axial bore 22 and an elongated central slot II in its mid-section.

Within the said bore is slidably mounted a block 50 I2 having threaded ends which protrude through the slot into engagement with an internally threaded sleeve I3 loosely mounted on the midsection 01' the body Ill. Sleeve I3 can be locked against a shoulder ll of the upper portion of 55 body ID by a threaded lock ring I5 screwed on to said body in position to engage the lower end of the sleeve. A stop pin I6 slidably mounted in the bore of the body has a stem I6b which projects up into a bore in the block I2, and is retained therein by a set screw threaded into a 5 hole in one end of the block and engaging a circumferential groove in the stem I612. The lower end of the body I0 is provided with an internally threaded shell I8 carrying a number of jaws I9 which are urged apart by compression springs 10 (not shown) interposed between adjacent jaws, and are normally held in contact with a pressure bushing 20 loosely mounted in the lower end of the bore 22. The construction of these jaws and compression springs is old and well known. 15

The drill 2I is inserted upwardly between the jaws I9 into the bore 22 of the body Ill until the shank end of said drill contacts the end of the spindle IGa of stop pin I6. Thereupon, by turning sleeve I3, the block I2 may be moved up or 20 down within slot II to adjust the stop pin I6 to any desirable position; and, being in contact with drill 2|, the latter can be thus set to protrude any desired distance from the shell I9 in accordance with the depth of the hole to be 25 drilled; In order to prevent block I2 or sleeve I3 from moving during the drilling operation, the lock ring I5, after positioning of the drill 2|, isscrewed tight against said sleeve I3. After accomplishing the correct setting of said drill, 3c the shell I8 is turned and tightened in the conventional manner causing jaws I9 to close and clamp drill 2I. The latter is then ready for the drilling operation, and rigidly held and supported at all times.

Besides setting the drill for the required depth of hole, another advantage of this adjustment of the stop relative to the tool gripping means lies in the possibility of using drills having broken shanks. Moreover by replacing stop pin It by a shorter or longer pin, drills of any standard length may be used in connection with the adjustable depth chuck described herein. Since the reduced portion of the stop may enter between the tool gripping jaws, drills of excessively short length may be used. Thus even the fluted portions which may occasionally break off the drills can be utilized.

The shell I8 is retained against rotation after it has been screwed up on the body Ill to bring the jaws I9 into gripping relation with the tool, by a lock spring 23 located in an internal annular groove in the upper end of the shell. An internal taper 24 is provided in the upper end of the body III to fit a driving spindle (not shown) whereby the drill is driven, and this taper may be threaded it necessary.

What is claimed is:

In a variable depth chuck having an elongated, externally threaded body portion with an axial bore intersected by radial slots, with an internally threaded adjusting sleeve located about a part of said portion and in threaded engagement therewith, and a clamp ring positioned on said portion to engage said sleeve for looking it in adjusted position thereon, and tool gripping jaws movable transversely of said bore to grip and release a tool, and a chuck cap secured to said body portion and arranged to effect movement of said jaws to and from tool gripping position;

a plunger movable in said bore. a reduced portion on said plunger constructed and arranged to abut against the end of a tool held by said jaws to prevent axial movement thereof, said reduced portion'being of such size that it can be moved between said jaws to back up said tool free from interference with said jaws while said tool is gripped therein, and means for coupling said plunger to said sleeve for axial adjustment in said bore, whereby said'plunger may be removed and other plungers provided with reduced portions of diflerent dimensions may be substituted therefor in said bore.

FREDERICK RUSSELL BROWN. 

